Once you've switched the feature on, you cannot simply fire off ill-considered emails late at night over the weekend. A window pops up to ask if you're sure, and sets a few mental arithmetic tasks you must answer to prove it, and release your message.

This blogger suggests that 7 other technologies - from eBay to instant messaging - would benefit from similar features, to stop regrettable purchases and other bloopers.

Those ideas are at least as sensible as the gmail feature. But once
you start thinking like that, all technologies would benefit from a
"goggles" mode - anything that makes a task easier also makes it easier
to do wrong or make mistakes.

Making those warnings smart enough
to know when you're really in danger of doing something you regret is a
real challenge. Can setting time windows really be enough to get Gmail
users to don their goggles? My guess is no. Perhaps a breathalyser
would be a better approach, or software like this able to tell what you're doing.

I
can see Gmail goggles finding fans that think of it as a productivity
enhancer - set it to be active during the day instead and you'll be
less likely to send non-business emails. And less inclined to disable
the feature in a fit of pique than your inebriated late-night persona
seemingly determined to embarrass themselves.